I was looking at some diagrams of exhaust setups for 95 m3's versus '96-'99 m3's and noticed that the obd1 setup is not in fact a true dual exhaust. There is a Y joint after the cats that the oxygen sensor plugs into, and then another Y that makes the rest of the exhaust dual again. Is this the same on my 1994 325is ? If so, how can I convert it to a true dual exhaust setup without comprimising my o2 sensor's readings? Can I plug it into just one of the exhaust pipes and still get fairly accurate readings?
I'd hate to install my headers, downpipes, free flowing cats, and dual inlet/outlet muffler if there is going to be a Y pipe in the middle of the works.